Role of transcranial Doppler in cerebral hyperperfusion syndrome

The benefit of carotid revascularization is hampered by occurrence of periprocedural cerebrovascular complications. Cerebral hyperperfusion syndrome (CHS) is a potentially life threatening complication occurring in approximately 3% of all patients following either carotid endarterectomy (CEA) or carotid angioplasty with stenting (CAS). CHS generally is defined as a transcranial Doppler (TCD) derived increase in cerebral blood flow of >100% over baseline. To reduce related morbidity and mortality early identification of patients at risk is essential. As such, TCD offers a technique for cerebral blood flow measurement that is nowadays the only applied and useful clinical monitoring tool for CHS prediction. Several studies have assessed the diagnostic value of TCD in the prediction of CHS and found promising results. However, results were based on a small number of cases and different definitions have been used to diagnose CHS. Moreover, the role of TCD in the onset of CHS has been studied most extensively following CEA, and it is unclear whether the findings of these studies can be generalized to patients undergoing CAS. Therefore we conclude that further studies in larger cohorts are required to assess the changes in cerebral hemodynamic in patients undergoing either CAS or CEA.